The present invention relates to a bumper arrangement for a motor vehicle.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
From the state-of-the-art bumper arrangements are known which are arranged on the front side or rear side of a motor vehicle. For this purpose the bumper arrangements have a cross member, which essentially extends over at least a part of the width of the motor vehicle body. The cross member is to be configured as bending-stiff as possible so that the different impact scenarios, for example collision with a pole, a bumper-to-bumper crash or also the collision with an obstacle, and here in particular with overlap, also known as offset-crash, are accounted for and an uncontrolled entering into the motor vehicle is prevented.
In order to absorb the kinetic energy generated in such a crash, such a known cross member is also coupled with the motor vehicle body, and in particular with the longitudinal members, via crash boxes. The crash boxes are configured so as to undergo deformation as a result of the impact and thus convert kinetic energy into deformation energy by cold deformation. In most cases the crash boxes are coupled with the front longitudinal members of the motor vehicle body in order to introduce the additional crash energy into them. The load path thus extends from the cross member via the crash boxes into the longitudinal members of the motor vehicle.
A good crash performance is associated with a high stiffness of the cross member and a high energy absorption capacity of the crash box and the cross member, which is realized by dimensioning the components large. However, these large dimensions of the components result in a high own weight and require a large amount of space.
The known bumper arrangements thus conflict with the goal of a smallest possible own weight, while at the same time providing good crash performance and requiring little installation space.
From EP 2 024 201 B1 a bumper arrangement is known which has a cross member which has a high stiffness as a result of various stiffening embossments and as a result of being subjected as a steel component to hot forming and press hardening technologies, while at the same time having small dimensions. In order to enable a sufficient overlap in case of a bumper-to-bumper crash with another motor vehicle, the cross member also has an asymmetric middle section to sufficiently vertically overlap a centerline of the cross member of an impacting motor vehicle. A problem associated therewith is however that an impact causes twisting about the longitudinal axis of the cross member.
Further, cross members are known from the state of the art that are made of lightweight metal extruded sections. For example from US 2015/0084355 A1 a bumper arrangement is known with a cross member as lightweight extruded section. In this case the overlap in case of a bumper-to-bumper crash and the stiffness of the cross member are realized by a corresponding total height of the cross member relative to the vertical direction of the motor vehicle.
It would therefore be desirable and advantageous to provide a bumper arrangement, which requires a small construction space while at the same time offering high crash performance and having a small own weight.